1. Field of the Invention
The present invention relates generally to the fields of cellular biology and the diagnosis of neoplastic disease. More specifically, the present invention relates to a novel extracellular serine protease termed Tumor Antigen Derived Gene-14 (TADG-14).
2. Description of the Related Art
Serine proteases comprise a family of protein degrading enzymes that serve a host of biological functions including activation of blood coagulation cascades, activation of growth and angiogenic factors and degradation of extracellular matrix components (1-4). In recent years, aberrant expression of serine proteases, such as plasminogen activator have been shown to correlate positively with the invasiveness and metastatic potential of tumor cells (3, 5-6). Presumably, this occurs by increasing the ability of the tumors to degrade extracellular matrix components either directly or indirectly through the proteolytic activation of other zymogenic proteases. More significantly, the serine protease known as the prostate specific antigen (PSA) has been used successfully as a tumor marker for the early diagnosis of prostate cancer due to its abnormal prevalence in the peripheral blood of these patients (7). Serine proteases play important roles in the cascade of events involved in the malignant process, and at least for prostate cancer, they provide sufficient signal to allow detection of early disease.
The prior art is deficient in the lack of effective means of screening to identify proteases overexpressed in carcinoma. The present invention fulfills this longstanding need and desire in the art.